Jurgen Klopp praised Fabinho for responding to the "birthday present" of being selected in his favourite position with a fine display against Red Star Belgrade.
The Brazil midfielder was at his combative best as the Reds went top of Group C thanks to goals from Roberto Firmino and Sadio Mane either side of a Mohamed Salah brace.
Fabinho was a reported £43.7million arrival from Monaco in May but has struggled to establish himself in Klopp's first XI amid Liverpool's impressive start to the campaign.
He made only his second start in the 4-0 win at Anfield on Wednesday, a day after turning 25, and thrived alongside Georginio Wijnaldum at the base of the midfield.
"Very good. Very, very good," Klopp said when asked about Fabinho's performance at a post-match news conference.
"The present for his birthday was not that he was in the line-up, it was that we played his favourite system with a double-six!
"He played really well and it was good to see. He was very aggressive and everything was there.
"For his first game for a while, his second from the beginning, it was good, really good. It is quite impressive what people saw."
And Klopp believes there is more to come from Fabinho, who can become a key figure in Liverpool's battle for honours on multiple fronts.
"It always helps a player if you play a good game – it helped us and helped him," he added. "That was the start, so let's carry on."
